Nanoporous metallic thin films prepared by dry processes

Nanoporous Pt and Au thin films were prepared by dry etching methods and compared to those prepared by conventional wet etching (dealloying). While reactive ion etching (RIE) and deep RIE methods did not yield nanoporous structures with high roughness factors (<5), gentle XeF2 dry etching yielded thin metallic nanoporous films (∼200 nm) with high enough roughness factors (∼40). The nanoporous films were as good as those prepared by wet etching using 3% HF solution in terms of thickness and roughness factors. Sensing performance of nanoporous Pt films prepared by XeF2 dry etching was as good as that of wet-chemically dealloyed nanoporous Pt films for glucose sensing.